Most conventional tapes for heavy industrial or commercial use have been manufactured using a calendering process wherein multiple layers (adhesive, base material, and release liner) are pressed together to form a laminated tape. The calendering process uses multiple rollers to press the bulk materials into sheets and then laminate them into a composite. This process is not conducive to applying a thin coating of substantially solids primer into the laminate between the adhesive and the release liner. Tapes with a integral primer are useful in numerous applications, including wrapping pipelines, maritime use, construction, and roofing applications. However, such tapes are more difficult to manufacture than standard commercial tape.
Other methods were examined that proved less successful than the present method. Spraying the substantially solids primer directly onto the adhesive after the base material and adhesive had been laminated was unworkable due to the high viscosity of the substantially solids primer. Applying a thin coating of substantially solids primer onto the laminate using a roller coating was unworkable because the primer has an aggressive tack that would not allow the primer to release from the coating roll to the laminate, even when the primer was heated. Coextruding multiple layers (base material, adhesive, and substantially solids primer) while laminating a release liner also had difficulties due to the high viscosity and aggressive tack of the primer.
Therefore, another method and apparatus had to be developed to manufacture tape with an integral primer.